Pianoforte construction



Feb. 23, 1937. M. MALE PIANOFORTE CONSTRUCTION Filed July 25, 1935 3 Sheets-Sheet 1 INVENTOR MLTONMLE..

BY x I a;

I ATTORNEYS Feb. 23, 1937.

M. MALE 2,072,005

PIANOFQRTE CONS TRUCTION Filed July 25, 1935 5 Sheets-Sheet 2 v 44 f 7 45 5 Z g 54 i" J i J 42 76 n I 2122 6 I I J5 Z INVENTOR MLTQNMLE BY m H ATTORNEYS Feb. 23, 1937. M. MALE PIANOFORTE CONSTRUCTION Filed July 25, v1935 5 Sheets-Sheet s INVENTOR. ML TO/VMALE. M f

ATTORNEYS Patented Feb. .23, 1937 UNITED STATES PATENT OFFICE PIANOFORTE CONSTRUCTION Milton Male, New York,

N. Y., assignor to United Application July 25, 1935, Serial No. 33,159

8 Claims.

This invention relates to metal pianoforte construction wherein a metal amplifying system is integrally united to a metal string supporting structure.

One feature of the invention relates particularly to improved string supporting means effective to adequately withstand the principal stresses caused by the tension of the strings. Another feature relates to improvements for bracing the metallic 1o amplifier plate so that it can readily withstand the local pressures applied thereto by the strings and yet not interfere with the proper vibratory response of the amplified plate.

A further feature relates to an improved marginal frame and related parts for supporting the sounding board, hitch pin and tuning pin plates. Other features relate to details of structure, design and arrangement of the parts individually and in combination, all as more particularly herein pointed 01.11%

One embodiment of the invention is illustrated in the accompanying drawings, in which- Fig. 1 is a longitudinal vertical section through a rear portion of the pianofo'rte; Fig. 2 is a plan L35 view thereof with the casing omitted; Fig. 3 is a detan section on line 3-3 of Fig. 2; Fig. 4 is a longitudinal vertical section through the front end of the pianoforte; Fig. 5 is a horizontal sec- 'tion on the staggered line 5-5 of Fig. 4; Fig. 6 is a plan view of the principal parts of the improved pianoforte with the casing and action omitted; Fig. '7 is a vertical longitudinal section on line l -1 of Fig. 6.

Referring in detail to the drawings, 10 represents a marginal frame which, as shown in Figs. 1

and '7, is formed of a structural member of substantially Z-shape in cross section. In plan view, this member is bent to the shape shown in Fig. 6 corresponding to the usual configuration of a grand pianoforte. The frame, as shown, includes substantially parallel side portions I2 and I4 joined by the rear curved portion l6. Extending transversely of the side portions I2 and I4, there is a cross member l8. Underframe braces 20 are provided to rigidify the structure and enable it to adequately withstand the forces acting thereon. A metallic amplifier plate 22 is welded at spaced points along its outer boundary to the upper flange 24 of the marginal frame by a plurality of spot welds, as indicated at 26. A hitch pin plate 28 is also welded to the amplifier plate and to the flange 24 of the marginal frame by the welds 26.

Secured to the underside of the amplifier plate,

I provide a plurality of ribs 30, preferably of hollow formation. For example, as shown in Fig.

these ribs are substantially U-shape in cross section. They are secured to the amplifier plate by Spot welds 32 which unite the flange feet 34 thereof as shown. To prevent any likelihood of chattering, I provide seam welds 36 which close the corners formed by the intersection of the edge of each foot flange 34 and the undersurface of the amplifier plate. The ribs are open ended and preferably they taper toward their outermost extremities. For example, in Fig. 1, it is noted that from the point 31 to the outer extremity 39, the ribs are of gradually diminishing depth. And I deem it important to terminate the outermost extremities of the ribs short of the line where the amplifier plate meets the marginal frame.

The amplifier plate of the present invention is preferably held in tension by the strings. This is in contrast with the condition prevailing in conventional wood soundboards, which are crowned with the result that the string tension L puts them in compression. By terminating the ribs, an appreciable distance from the point where the amplifier plate is secured to the frame, I insure adequate flexibility of the plate, thus greatly improving the acoustic response as compared to prior types of Soundboards. The diminishing of the depth of the ribs near the ends also contributes to the increased flexibility of the structure as a whole. By reason of the fact that the flange feet of the ribs are united to the amplifier plate by spot welds, no extraneous metal is introduced, thus the entire amplifier structure is made homogeneous. All likelihood of chattering is avoided by the seam welds 36 above referred to. A suitable bridge 38 is welded to the upper surface of the amplifier plate, as shown.

At the forward end of the pianoforte, I provide a tuning pin plate referred to generally at 40, which includes a transversely extending member 42 and a substantially horizontal member 44.

The tuning pin plate is supported from the cross member ill in an improved manner by torsion braces 46. These torsion braces are secured at their rear portions to the transverse member l8 and they extend upwardly and forwardly and are united at their forward ends to the tuning pin plate. Thus, it is apparent that they cross the plane of the amplifier plate as well as the plane of the strings 48.

The strings 48 are secured at their rearward ends to hitch pins 50 and at their forward ends to tuning pins 52, the latter being carried by the tuning pin plate 40 and usually engaging a wooden member 54 :su'itably secured to the tumng pin plate.

pin plate.

The pull of the strings on the tuning pins acting in a plane above the tuning plate tends to twist the latter with a torsional effect urging the rear portion downward and the front portion upward.

Heretofore, it has been one practice to resist this twisting tendency by means of so-called bars located wholly above the plane of the amplifier or sounding board and extending from the tuning pin plate to the hitch pin plate, which bars in such old construction serve to withstand the direct pull of the strings. Such old bars were neces sarily located in the same horizontal plane as the dampers above the strings and of necessity were of considerable width, ranging from one inch to one and one-quarter inches in order to give them sufficient strength to withstand the direct pull of the strings whose total stress in conventional pianofortes ranges from fifteen to twenty tons.

Since no damper must conflict with the bars, it

has been prior practice to skew or splay the rear portion of several keys on each side of each of the so-called bars of the old constructions, so as to provide the necessary clearance. And, since the narrowest of such old bars were of one inch Width,

the splay of necessity has been at least one-half inch on each side of the bar on a key of about nineteen inch length. Of course,'the hammers were required to be necessarily splayed. This old practice adds to expense in constructing the action and. also disrupts the uniformity of tonegradation between the adjacent unisons, it being understood that such unisons refer to a group of strings, usually two or three for each note.

In my improved construction, as will be apparent from Figs. 4 and 5, all of the keys 5| are perfectly straight and parallel and thus require no expensive splaying or offsetting. The only special work on the keys is the provision of shallow notches 52' formed in certain of them, so as to provide space for the action supports 55, usually known as hangers. These hangers support the conventional type of hammers 56 which are actuated through conventional piano action members, such as indicated, upon the striking of mately three-eighths of an inch in thickness as measured in the direction transverse to that of the strings. Hence, the shallow notching in the keys adjacent the hangers is sufficient to accommodate them.

In a known old practice, the wide bars referred to have been eliminated and their function as struts was transferred to larger and heavier lateral rim members connected to stronger and heavier sections in a tuning pin plate and hitch In this old practice, in the case of the tuning pin plate, it has been found impractical to use a section of reasonable size that will satisfactorily withstand the'twisting or torsional effect referred to and has resulted in the rear edge of compared to the old construction, where the bars are eliminated for the reason that with the aid of my improvement, advantages of uniformity of tone-gradation and economy in constructing the action are combined with an inexpensive and simple means for positively and effectively stiffening the tuning pin plate.

Since the twisting tendency of the tuning pin plate is downward, my torsion braces 46 are made of considerable depth, the only limitation in this respect being the need of clearing the supports for the action. In order to permit of uniform parallel keys, I make the braces comparatively thin. I have determined that I can secure an adequate resistance to torsion by using braces of approximately one-quarter of an inch thick. Since this amount is less than the normal thickness of the action hangers 55, my improvement involves no special construction of the keys, hammers, or dampers. Therefore, I adopt the rule that the thickness of the torsion braces 46 shall be not greater than that of the action hangers 55. my improved thin torsion brace member which crosses the plane of the springs makes it unnecessary to splay the strings apart. Thus a substantially uniform spacing of the string unisons can be employed which, of course, will match up Ii with the uniform spacing of the action hammers. Also, with my arrangement of thin torsion braces, substantially all of the keys are made straight, parallel and uniformly spaced. This results in important manufacturing economies, as con old construction of necessity had to be varied to provide room for such wide bars.

Another feature of the invention is the form of the marginal frame member. Where the amplifying plate is to be integrally united to the string supporting structure, it is important that such marginal member be of such design and arrangement that it can adequately resist bending in a vertical plane, that it shall have ample strength as a strut about both of its sectional axes, that it shall be accessible for attachment by welding of the underframe braces and that it shall be accessible for welded attachment of the soundboard and the hitch plate, and that it shall be readily insertable and connectible with the case of the pianoforte.

To meet these requirements, I employ the marginal frame having the sectional form of a Z. Its depth .gives great strength to resist vertical bending and the fact that its upper and lower flanges are on opposite sides of its web makes it an efficient strut about both of its axes. The upper flange 24 is in a plane contiguous to that of the marginal portions of the amplifier plate 22 and the hitch pin plate 28. This facilitates integrally uniting all of these parts by a line of spot welds. The web of the marginal frame member If) is at right angles to the plane of the braces 20 and thereby an adequate surface is provided to which the web members of such braces can be welded. The upper flange of the marginal frame extends outwardly and the inner flange extends inwardly as shown. This permits the entire assembly to be dropped into its final position in the case and to be supported on blocks or similar members 58 secured to the exterior case or to a continuous rim on the casing.

The hitch plate 28, as best shown in Fig. l, is of substantially Z-shape in cross section comprising the upper plate-like portion 60 which is connected to a web portion 62 to a flange portion 64,

It is also apparent that utilizing which is welded to the amplifier plate and the upper flange of the marginal frame as shown.

It is important that the stresses imposed by the strings on the hitch pin plate be transferred to the marginal portion of the amplifying systern. If that portion of the hitch pin plate to which the strings are attached were in approximately the same plane as the amplifier plate, it is obvious that the strings would not be separated, from said plate, by an amount sufficient for the insertion of bridges of adequate height. It is for this reason that I elevate the portion 60 of the hitch pin plate. Instead of making this elevated area slope gradually from the line of the hitch pins to the outer rim of the marginal frame, which would require the height of the hitch pin plate to vary from point to point and would involve deep and irregular crowning, I maintain the elevated portion of the hitch-plate in a horizontal plane spaced above the amplifier plate, which plane extends outwardly to the inner edge of the flange of the marginal frame. At this zone, the hitch pin plate is pressed down to form the web 62 and the outwardly extending flange 64. The web portion 62 follows the plan of the sounding board and marginal frame, as will be apparent from the drawings. This arrangement simplifies the manufacture of the hitch pin plate because its height is kept constant. But, special provision must be made to prevent the pull on the strings from flattening out the Z-shape hitch pin plate.

This is particularly important, where the hitch pin plate is made of rolled metal, as distinguished from heavy cast metal and where the parts are to be made of light gauge stock. To meet this problem, I provide stiffeners 66 and 68, the stiffeners 66 being welded along the edges contiguous to the upper portion 60 and web portions 92 and to the flange portion 64. Thus, it is clear that the stiffeners extend around the corner formed by the web portion 62 and the plate portion 60 thereof. The underside stiffeners 68 are similarly welded in the corner formed by the intersection of the undersurface of the plate 60 and the inner surface of the web 62. At the inner extremity of the portion 60 of the hitch pin plate, I provide a depending flange 10, which usually terminates approximately three-eighths of an inch from the plane of the upper face of the soundboard, this amount being sufiicient as shown in practice and determined by the fact that downward deflection of the hitch pin plate in response to the pull of the strings should bring the front flange 10 not closer than one-quarter inch from the amplifier plate, in order to prevent interference with its acoustic response.

While I have described quite precisely the specific design and arrangement of the embodiment of the invention herein illustrated, it is not to be construed that I am limited thereto since various modifications and substitutions of equivalents may be made by those skilled in the art without departure from the invention as defined in the appended claims.

What I claim is:-

1. A pianoforte comprising a metal marginal frame, a metal amplifier plate secured thereto, the frame including a front cross member, a tuning pin plate spaced forwardly and upwardly from the cross member, and torsion braces of thin rolled metal secured to the latter and cross ing the plane of said amplifier plate and supporting said tuning pin plate.

2. A pianoforte comprising a metal marginal frame, a metal amplifier plate secured thereto, the frame'including a front cross member, a tuning pin plate spaced forwardly and upwardly from the cross member, a hitch pin plate secured to said marginal frame, hitch pins thereon and tuning pins carried by the tuning pin plate, strings engaging the hitch and tuning pins, han

rs supporting action hammers which coact with said strings, keys for actuating said hammers and torsion braces joining the cross member to the tuning pin plate and crossing the plane of said strings and whose thickness measured transversely of the strings is not greater than the thickness of said hangers measured in the same direction, substantially all of the keys of the pianoforte for actuating substantially all of the hammers being straight and parallel with one another throughout their entire lengths.

3. A pianoforte comprising a metal marginal frame, an amplifier plate secured thereto, a hitch .in plate supported by said frame, a tuning pin plate, a cross member forming part of said frame, strings, hitch pins and tuning pins therefor, hangers supporting hammers for coaction with said strings, keys for actuating the hammers, members crossing the plane of said strings and supporting the hitch pin plate from said cross member, the thickness of the hangers as measured transversely of the strings being less than the transverse distance between the strings of different notes, and the thickness of said members measured transversely of the strings being not greater than that of said hangers, substantially all of the keys of the pianoforte for actuating substantially all of the hammers being straight and parallel with one another throughout their entire lengths.

4. A pianoforte comprising a metal marginal frame of Z-shape in cross section, an amplifier plate of metal welded to one of the flanges thereof, a cross member and bracing elements between the latter and the Z-shaped frame, a hitch pin plat-e secured to said Z-mernber, a tuning pin plate spaced from said cross member, strings supported by pins carried by said hitch and. tuning pin plates and brace members less than threeeighths of an inch thick crossing the plane of said strings and connecting the tuning pin plate to said cross member.

5. A pianoforte comprising a flanged metal marginal frame, a wrought metal amplifier plate and a metal hitch pin plate both secured to the same flange of said frame, hitch pins and strings secured thereto, said hitch plate being bent to substantially Z- hape in cross section with its flanges substantially parallel with the plane of one flange of the marginal frame and notch-ed stiffeners secured edgewise in different horizontal planes to the hitch plate adapted to resist the tendency of the tension of said strings to distort said. hitch plate.

6. A pianoforte comprising a marginal rolled metal frame of Z-shaped cross section, a wrought metal amplifier plate welded to the upper flange thereof, a hitch pin plate of wrought metal having a flange welded to the face of the amplifier plate and a portion parallel therewith carrying a plurality of hitch pins and joined by a web to said flange, and notched stiffeners Welded edgewise in different horizontal planes to the hitch pin plate and effective to resist the tendency of the string tension todistort it.

7. A pianoforte comprising a marginal rolled metal frame of Z-shaped cross-section, a metal amplifier plate secured thereto, a hitch pin plate of wrought metal having a flange secured to the face of the amplifier plate and a portion parallel therewith carrying a plurality of hitch pins and joined by a web to said flange, and notched stifieners having respective parts welded edgewise to said parallel portion and having other parts welded edgewise to the said web and flange of said hitch pin plate.

8. A pianoforte comprising a marginal rolled metal frame of Z-shaped cross section, a metal amplifier plate secured thereto, a hitch pin plate of wrought metal having a flange secured to the face of the amplifier plate and a portion parallel therewith carrying a plurality of hitch pins and joined by a Web to said flange, and a plurality of plate-like stifieners notched to fit to the corners formed by the intersection of the web and said pin carrying portion and welded edgewise thereto to resist the tendency of the string tension to pull the hitch pin portion into the plane of the flange portion thereof.

MILTON MALE. 

